Nanostructured Materials for Microfluidic Sensing Application

Nanostructured thin films were assembled on interdigited microelectrode (IME) arrays as sensitive interfacial materials of an electrochemical detector, which can be integrated into microfluidic sensor devices. The goal is to produce sensor devices at extremes of miniaturization. The IME were created on glass wafers using conventional lithographic techniques. Open channels were etched on quartz or glass, and covered by PDMS materials, which were created using soft-lithography. The capability of chemical recognition was provided by the ligand framework structures of the nanostructured thin films on the electrode surface. A model system for such nanostructures involved the use of monolayer-capped gold nanoparticles of ∼2 nm core sizes which were assembled by carboxylic acid functionalized alkyl thiol linkers. The detection of dopamine was studied as a redox probe to test the feasibility of the microfluidic device. Results of cyclic voltammetric and chronoamperometric experiments are presented. Implications of the findings to the development of sensitive, selective, rapid and portable microanalytical devices for chemical/biological sensing are also discussed.